In a technological era where the world is connected via a highly-advanced internet network, humans interact with artificial intelligence units known as Net Navis. Housed within PET handheld devices, humans and Net Navis coexist between the real and cyber worlds as friends and allies. Net Navis are designed for various tasks, most specifically battle against viruses and rogue Net Navis operated by net crime syndicates. A young boy named Netto Hikari receives his first Net Navi named Rockman and the two become an unstoppable net-battling duo. Together, they thwart the evil schemes of criminals like World Three and the Netmafia Gospel.